The London Independent & The Observr & BBC Online – 2005-11-24 22:32:46
http://news.independent.co.uk/environment/article328217.ece
The Big Thaw
Geoffrey Lean / The Independent
LONDON (November 20, 2005) — Greenland’s glaciers have begun to race towards the ocean, leading scientists to predict that the vast island’s ice cap is approaching irreversible meltdown, The Independent on Sunday can reveal.
Research to be published in a few days’ time shows how glaciers that have been stable for centuries have started to shrink dramatically as temperatures in the Arctic have soared with global warming. On top of this, record amounts of the ice cap’s surface turned to water this summer.
The two developments — the most alarming manifestations of climate change to date — suggest that the ice cap is melting far more rapidly than scientists had thought, with immense consequences for civilization and the planet. Its complete disappearance would raise the levels of the world’s seas by 20 feet, spelling inundation for London and other coastal cities around the globe, along with much of low-lying countries such as Bangladesh.
More immediately, the vast amount of fresh water discharged into the ocean as the ice melts threatens to shut down the Gulf Stream, which protects Britain and the rest of northern Europe from a freezing climate like that of Labrador.
The revelations, which follow the announcement that the melting of sea ice in the Arctic also reached record levels this summer, come as the world’s governments are about to embark on new negotiations about how to combat global warming.
This week they will meet in Montreal for the first formal talks on whether there should be a new international treaty on cutting the pollution that causes climate change after the Kyoto protocol expires in seven years’ time. Writing in The Independent yesterday, Tony Blair called the meeting “crucial”, adding that it “must start to shape an inclusive global solution”. But little progress is expected, largely because of continued obstruction from President George Bush.
The new evidence from Greenland, to be published in the journal Geophysical Research Letters, shows a sudden decline in the giant Helheim glacier, a river of ice that grinds down from the inland ice cap to the sea through a narrow rift in the mountain range on the island’s east coast.
Professor Slawek Tulaczyk, of the Department of Earth Sciences at the University of California, Santa Cruz, told the IoS that the glacier had dropped 100 feet this summer.
Over the past four years, the research adds, the front of the glacier — which has remained in the same place since records began — has retreated four and a half miles. As it has retreated and thinned, the effects have spread inland “very fast indeed”, says Professor Tulaczyk. As the centre of the Greenland ice cap is only 150 miles away, the researchers fear that it, too, will soon be affected.
The research echoes disturbing studies on the opposite side of Greenland: the giant Jakobshavn glacier — at four miles wide and 1,000 feet thick the biggest on the landmass — is now moving towards the sea at a rate of 113 feet a year; the normal annual speed of a glacier is just one foot.
The studies have found that water from melted ice on the surface is percolating down through holes on the glacier until it forms a layer between it and the rock below, slightly lifting it and moving it toward the sea as if on a conveyor belt. This one glacier alone is reckoned now to be responsible for 3 per cent of the annual rise of sea levels worldwide.
“We may be very close to the threshold where the Greenland ice cap will melt irreversibly,” says Tavi Murray, professor of glaciology at the University of Wales. Professor Tulaczyk adds: “The observations that we are seeing now point in that direction.”
Until now, scientists believed the ice cap would take 1,000 years to melt entirely, but Ian Howat, who is working with Professor Tulaczyk, says the new developments could “easily” cut this time “in half”.
There is also a more immediate danger as the melting ice threatens to disrupt the Gulf Stream, responsible for Britain’s mild climate. The current, which brings us as much heat in winter as we get from the sun, is driven by very salty water sinking off Greenland. This drives a deep current of cold ocean southwards, in turn forcing the warm water north.
Research at the Woods Hole Oceanographic Institute in Massachusetts has shown, that even before the glaciers started accelerating, the water in the North Atlantic was getting fresher in what it describes as “the largest and most dramatic oceanic change ever measured in the era of modern instruments”.
Even before these discoveries, scientists had shortened to evens the odds on the Gulf Stream failing this century. When it failed before, 12,700 years ago, Britain was covered in permafrost for 1,300 years.
Millions Face Glacier Catastrophe
as Global Warming Hits the Himalayas
Robin McKie / The Observer
LONDON (November 20, 2005) — Nawa Jigtar was working in the village of Ghat, in Nepal, when the sound of crashing sent him rushing out of his home. He emerged to see his herd of cattle being swept away by a wall of water.
Jigtar and his fellow villagers were able to scramble to safety. They were lucky: ‘If it had come at night, none of us would have survived.’
Ghat was destroyed when a lake, high in the Himalayas, burst its banks. Swollen with glacier meltwaters, its walls of rock and ice had suddenly disintegrated. Several million cubic metres of water crashed down the mountain.
When Ghat was destroyed, in 1985, such incidents were rare — but not any more. Last week, scientists revealed that there has been a tenfold jump in such catastrophes in the past two decades, the result of global warming. Himalayan glacier lakes are filling up with more and more melted ice and 24 of them are now poised to burst their banks in Bhutan, with a similar number at risk in Nepal.
But that is just the beginning, a report in Nature said last week. Future disasters around the Himalayas will include ‘floods, droughts, land erosion, biodiversity loss and changes in rainfall and the monsoon’.
The roof of the world is changing, as can be seen by Nepal’s Khumbu glacier, where Hillary and Tenzing began their 1953 Everest expedition. It has retreated three miles since their ascent. Almost 95 per cent of Himalayan glaciers are also shrinking — and that kind of ice loss has profound implications, not just for Nepal and Bhutan, but for surrounding nations, including China, India and Pakistan.
Eventually, the Himalayan glaciers will shrink so much their meltwaters will dry up, say scientists. Catastrophes like Ghat will die out. At the same time, rivers fed by these melted glaciers — such as the Indus, Yellow River and Mekong — will turn to trickles. Drinking and irrigation water will disappear. Hundreds of millions of people will be affected.
‘There is a short-term danger of too much water coming out the Himalayas and a greater long-term danger of there not being enough,’ said Dr Phil Porter, of the University of Hertfordshire. ‘Either way, it is easy to pinpoint the cause: global warming.’
According to Nature, temperatures in the region have increased by more than 1C recently and are set to rise by a further 1.2C by 2050, and by 3C by the end of the century. This heating has already caused 24 of Bhutan’s glacial lakes to reach ‘potentially dangerous’ status, according to government officials. Nepal is similarly affected.
‘A glacier lake catastrophe happened once in a decade 50 years ago,’ said UK geologist John Reynolds, whose company advises Nepal. ‘Five years ago, they were happening every three years. By 2010, a glacial lake catastrophe will happen every year.’
An example of the impact is provided by Luggye Tsho, in Bhutan, which burst its banks in 1994, sweeping 10 million cubic metres of water down the mountain. It struck Panukha, 50 miles away, killing 21 people.
Now a nearby lake, below the Thorthormi glacier, is in imminent danger of bursting. That could release 50 million cubic metres of water, a flood reaching to northern India 150 miles downstream.
‘Mountains were once considered indomitable, unchanging and impregnable,’ said Klaus Tipfer, of the United Nations Environment Programme. ‘We are learning they are as vulnerable to environmental threats as oceans, grasslands and forest.’
Not only villages are under threat: Nepal has built an array of hydroelectric plants and is now selling electricity to India and other countries. But these could be destroyed in coming years, warned Reynolds. ‘A similar lake burst near Machu Picchu in Peru recently destroyed an entire hydroelectric plant. The same thing is waiting to happen in Nepal.’
Even worse, when Nepal’s glaciers melt, there could be no water to drive the plants. ‘The region faces losing its most dependable source of fresh water,’ said Mike Hambrey, of the University of Wales.
A Greenpeace report last month suggested that the region is already experiencing serious loss of vegetation. In the long term, starvation is a real threat.
‘The man in the street in Britain still isn’t sure about the dangers posed by global warming,’ said Porter. ‘But people living in the Himalayas know about it now. They are having to deal with its consequences every day.’
Additional reporting: Amelia Gentleman and Felix Lowe
Guardian Unlimited © Guardian Newspapers Limited 2005
CO2 ‘Highest for 650,000 Years’
Richard Black / BBC News Online
Current levels of the greenhouse gases carbon dioxide and methane in the atmosphere are higher now than at any time in the last 650,000 years. That is the conclusion of new European studies looking at ice taken from 3km below the surface of Antarctica.
The scientists say their research shows present day warming to be exceptional. Other research, also published in the journal Science, suggests that sea levels may be rising twice as fast now as in previous centuries.
The evidence on atmospheric concentrations comes from an Antarctic region called Dome Concordia (Dome C).
Over a five year period commencing in 1999, scientists working with the European Project for Ice Coring in Antarctica (Epica) have drilled 3,270m into the Dome C ice, which equates to drilling nearly 900,000 years back in time.
Gas bubbles trapped as the ice formed yield important evidence of the mixture of gases present in the atmosphere at that time, and of temperature.
“One of the most important things is we can put current levels of carbon dioxide and methane into a long-term context,” said project leader Thomas Stocker from the University of Bern, Switzerland. “We find that CO2 is about 30% higher than at any time, and methane 130% higher than at any time; and the rates of increase are absolutely exceptional: for CO2, 200 times faster than at any time in the last 650,000 years.”
Stable Relationship
Last year, the Epica team released its first data. The latest two papers analyse gas composition and temperature dating back 650,000 years. This extends the picture drawn by another Antarctic ice core taken near Lake Vostok which looked 440,000 years into the past.
The extra data is crucial because around 420,000 years there appears to have been a significant shift in the Earth’s long-term climate patterns. Before and after this date, the planet went through 100,000 year cycles of alternating cold glacial and warm interglacial periods.
But around the 420,000 year mark, the precise pattern changed, with the contrast between warm and cold conditions becoming much more marked. The Dome C core gives data from six cycles of glaciation and warming; two from before this change, four from after.
“We found a very tight relationship between CO2 and temperature even before 420,000 years,” said Professor Stocker. “The fact that the relationship holds across the transition between climatic regimes is a very strong indication of the important role of CO2 in climate regulation.” Epica scientists will now try to extend their analysis further back in time.
Water Rise
Another study reported in the same journal claims that for the last 150 years, sea levels have been rising twice as fast as in previous centuries.
Using data from tidal gauges and reviewing findings from many previous studies, US researchers have constructed a new sea level record covering the last 100 million years. They calculate the present rate of rise at 2mm per year.
“The main thing that’s changed since the 19th Century and the beginning of modern observation has been the widespread increase in fossil fuel use and more greenhouse gases,” said Kenneth Miller from Rutgers University.
The Intergovernmental Panel on Climate Change, the body which collates scientific evidence for policymakers, concludes that sea level rose by 1-2cm during the last century, and will rise by anything up to 88cm by the end of this century.
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